1. Field of the Invention
The present invention relates to apparatus and methods for determining whether a person is recognized by reference to the eyes of this person. More particularly, the present invention relates to apparatus and methods for recognizing humans by their distinct and individual iris patterns. Most specifically, the present invention relates to an apparatus and method for determining where in a field of view the eyes of a person to be recognized are located, so that closer inspection of the eyes and of the iris of at least one of these eyes can be conducted for recognition purposes.
2. Related Technology
It is well known that humans have individual and distinct fingerprints. Methods and apparatus have been developed for identifying humans by reference to these fingerprints. Such methods of fingerprint identification have a long history, starting with entirely manual and laborious comparisons of fingerprints located at a crime scene, for example, to ink images of the fingerprints of known criminals. Understandably, such manual comparison methods are laborious and very time consuming. As the population increases, and the numbers of people with criminal records increases also, the job of finding a match between fingerprints from a crime scene and paper records of fingerprints becomes simply overwhelming. Recently, automated methods and apparatus have been developed to speed such finger print identification processes.
Similarly, it is now becoming increasingly well known that the human iris has a level and individuality and distinctiveness that exceeds even that of the human fingerprint. In the mid-1980's, Doctors Leonard Flom and Aran Safir showed that the iris is unique among individuals. These doctors patented a method of using the human iris to identify individual people, and formed a company named IriScan, which is a leader in the field of identifying people from their iris patterns. Attention is directed to U.S. Pat. No. 4,641,349, issued Feb. 3, 1987 to Drs. From and Safir.
Another worker in this field who is credited with inventing some of the current technology is Doctor John G. Daugman of the Computer Laboratory of the University of Cambridge. Attention is directed to U.S. Pat. No. 5,291,560, issued Mar. 1, 1994. This patent is believed to deal with the problem of iris pattern signal processing and correlation. However, the burden of comparing iris patterns to a data base of such patterns would be virtually impossible without the application of similar sorting technologies from fingerprint identification. Further, iris patterns are being currently treated as bar codes, the sorting and identification technology for which is already well developed.
The IriScan technology is believed to require a person who wishes to be identified to look with a selected eye through a portal. The portal leads into a machine which captures an image of the iris of the eye so presented. The Sensar Company is believed to use IriScan technology in their Sensar Secure identification system. Another system believed to by similar is offered by Oki Electric Industries Co. Ltd. Of Japan, and is known as an Iris Personal Identification System. This latter system is believed to rely upon a video camera which captures a visible light image of the subject, and a pattern recognition software which picks out the subjects face from the background image. Once the subject's face is identified in the field of view then further pattern recognition is conducted to identify and locate a selected eye on the subject's face. This location is then provided to a servo system which directs a fine-focus telephoto video camera toward the location of the person's selected eye. This fine focus video camera then captures an image of the selected eye of the subject, including the iris of this eye, for further processing into a "bar code" pattern which allows definite recognition of the subject.
In view of the above, it is easily understood that the image processing burden on an identification system is substantial in order to pick out the person's face, and the selected eye of a person, and to do this job fast enough to allow such a system to be accepted for use. For example, the systems can be used at airports for passenger identification, and at ATM machines, for example. However, the identification of the person before the machine must be performed in a matter of a few seconds, or desirably less. As can be appreciated, in the event that the pattern recognition software mistakenly directs the fine focus video camera to a location other than the selected eye of the person, the system will not capture an image of an eye it can recognize even when the subject should be recognizable to the system. This inability of the current technology to reliably and quickly locate a selected eye of a person within a field of view to be surveyed represents a serious shortcoming in the conventional technology, and one which must be overcome if iris identification systems are to receive widespread public acceptance.